1. Field of the Invention
The present invention relates generally to a method for controlling electromechanical valves in an internal combustion engine.
2. Background of the Invention
An electromechanically operated poppet valve in the cylinder head of an internal combustion, as disclosed in U.S. Pat. No. 4,455,543, is actuated by energizing and de-energizing electromagnets acting upon an armature coupled to the poppet valve. Because the actuation of the electromagnets is controlled by an electronic control unit, valve opening and closing events occur independently of engine rotation. In conventional engines with camshaft actuated valves, which have timings based on engine rotation, air delivery to the cylinders is controlled by a throttle valve placed in the inlet duct of the engine. In contrast, electromechanical valves are capable of controlling air delivery based on valve timing, thereby providing a thermal efficiency improvement over throttled operation of a conventional engine.
However, a drawback to electromechanical valves is the amount of electrical energy consumed in actuating them. The inventors of the present invention have recognized a method to operate electromechanical valves in a manner which consumes less electrical energy than prior methods.